|
|
|
Pronunciation |
|
(a
moks i SIL
in) |

|
|
U.S. Brand
Names |
|
Amoxil®; Biomox®;
Trimox®; Wymox® |

|
|
Generic
Available |
|
Yes |

|
|
Canadian Brand
Names |
|
Apo®-Amoxi; Novamoxin®; Nu-Amoxi;
Pro-Amox® |

|
|
Synonyms |
|
Amoxicillin Trihydrate; Amoxycillin;
p-Hydroxyampicillin |

|
|
Pharmacological Index |
|
Antibiotic, Penicillin |

|
|
Use |
|
Dental: Antibiotic for standard prophylactic regimen for dental patients who
are at risk
Medical: Treatment of otitis media, sinusitis, and infections caused by
susceptible organisms involving the respiratory tract, skin, and urinary tract;
prophylaxis of bacterial endocarditis in patients undergoing surgical or dental
procedures; approved in combination with clarithromycin and lansoprazole for
eradication of H. pylori; in patients with active duodenal ulcer disease
or a 1-year history of duodenal ulcer. The combined use of lansoprazole and
amoxicillin is approved for patients unable to take clarithromycin.
|

|
|
Pregnancy Risk
Factor |
|
B |

|
|
Contraindications |
|
Hypersensitivity to amoxicillin, penicillin, or any
component |

|
|
Warnings/Precautions |
|
In patients with renal impairment, doses and/or frequency of administration
should be modified in response to the degree of renal impairment; a high
percentage of patients with infectious mononucleosis have developed rash during
therapy with amoxicillin; a low incidence of cross-allergy with other
beta-lactams and cephalosporins exists |

|
|
Adverse
Reactions |
|
1% to 10%:
Central nervous system: Fever
Dermatologic: Urticaria, rash
Miscellaneous: Allergic reactions (includes serum sickness, rash, angioedema,
bronchospasm, hypotension, etc)
<1%: Seizures, anxiety, confusion, hallucinations, depression (with large
doses or patients with renal dysfunction), nausea, vomiting, leukopenia,
neutropenia, thrombocytopenia, jaundice, interstitial nephritis
|

|
|
Overdosage/Toxicology |
|
Symptoms of penicillin overdose include neuromuscular hypersensitivity
(agitation, hallucinations, asterixis, encephalopathy, confusion, and seizures)
and electrolyte imbalance with potassium or sodium salts, especially in renal
failure
Hemodialysis may be helpful to aid in the removal of the drug from the blood,
otherwise most treatment is supportive or symptom directed |

|
|
Drug
Interactions |
|
Decreased effect: Efficacy of oral contraceptives may be reduced
Increased effect: Disulfiram, probenecid may increase amoxicillin levels
Increased toxicity: Allopurinol theoretically has an additive potential for
amoxicillin rash |

|
|
Stability |
|
Oral suspension remains stable for 7 days at room temperature or 14 days if
refrigerated; unit dose antibiotic oral syringes are stable for 48
hours |

|
|
Mechanism of
Action |
|
Inhibits bacterial cell wall synthesis by binding to one or more of the
penicillin binding proteins (PBPs); which in turn inhibits the final
transpeptidation step of peptidoglycan synthesis in bacterial cell walls, thus
inhibiting cell wall biosynthesis. Bacteria eventually lyse due to ongoing
activity of cell wall autolytic enzymes (autolysins and murein hydrolases) while
cell wall assembly is arrested. |

|
|
Pharmacodynamics/Kinetics |
|
Absorption: Oral: Rapid and nearly complete; food does not interfere
Distribution: Widely distributed to most body fluids and bone; penetration
into cells, eyes, and across normal meninges is poor
Protein binding: 17% to 20%
Ratio of CSF to blood: Normal meninges: <1%; Inflamed meninges: 8% to 90%
Metabolism: Partial
Half-life:
Neonates, full-term: 3.7 hours
Infants and Children: 1-2 hours
Adults with normal renal function: 0.7-1.4 hours
Patients with Clcr <10 mL/minute: 7-21 hours
Time to peak: 2 hours (capsule) and 1 hour (suspension)
Elimination: Renal excretion (80% as unchanged drug); lower in neonates
|

|
|
Usual Dosage |
|
Oral:
Subacute bacterial endocarditis prophylaxis: 50 mg/kg 1 hour before procedure
Adults: 250-500 mg every 8 hours or 500-875 mg twice daily; maximum dose: 2-3
g/day
Endocarditis prophylaxis: 2 g 1 hour before procedure
Helicobacter pylori: 250-500 mg 3 times/day or 500-875 mg twice
daily; clinically effective treatment regimens include triple therapy with
amoxicillin or tetracycline, metronidazole, and bismuth subsalicylate;
amoxicillin, metronidazole, and an H2-receptor antagonist;
amoxicillin, lansoprazole, and clarithromycin.
Dosing interval in renal impairment:
Clcr 10-50 mL/minute: Administer every 12 hours
Clcr <10 mL/minute: Administer every 24 hours
Dialysis: Moderately dialyzable (20% to 50%) by hemo- or peritoneal dialysis;
approximately 50 mg of amoxicillin per liter of filtrate is removed by
continuous arteriovenous or venovenous hemofiltration (CAVH); dose as per
Clcr <10 mL/minute guidelines |

|
|
Dietary
Considerations |
|
Food: May be taken with food |

|
|
Monitoring
Parameters |
|
With prolonged therapy, monitor renal, hepatic, and hematologic function
periodically; assess patient at beginning and throughout therapy for infection;
monitor for signs of anaphylaxis during first dose |

|
|
Test
Interactions |
|
May interfere with urinary glucose tests using cupric sulfate (Benedict's
solution, Clinitest®); may inactivate aminoglycosides
in vitro |

|
|
Mental Health: Effects
on Mental Status |
|
Rarely large doses may produce confusion, hallucinations, and depression;
penicillins have been reported to cause apprehension, illusions, agitation,
insomnia, depersonalization, and encephalopathy |

|
|
Mental Health:
Effects on Psychiatric
Treatment |
|
Disulfiram may increase amoxicillin levels |

|
|
Dental Health: Local
Anesthetic/Vasoconstrictor
Precautions |
|
No information available to require special precautions |

|
|
Dental Health:
Effects on Dental Treatment |
|
Prolonged use of penicillins may lead to development of oral
candidiasis |

|
|
Patient
Information |
|
Take entire prescription, even if you are feeling better. Take at equal
intervals around-the-clock; may be taken with milk, juice, or food. You may
experience nausea or vomiting (small frequent meals, frequent mouth care,
sucking lozenges, or chewing gum may help). If diabetic, drug may cause false
tests with Clinitest® urine glucose monitoring; use of
glucose oxidase methods (Clinistix®) or serum glucose
monitoring is preferable. This drug may interfere with oral contraceptives; an
alternate form of birth control should be used. Report rash; unusual diarrhea;
vaginal itching, burning, or pain; unresolved vomiting or constipation; fever or
chills; unusual bruising or bleeding; or if condition being treated worsens or
does not improve by the time prescription is completed. |

|
|
Nursing
Implications |
|
Assess patient at beginning and throughout therapy for infection; observe for
signs and symptoms of anaphylaxis; obtain specimens for C&S before the first
dose; administer around-the-clock rather than 3 times/day, etc, (ie, 8-4-12, not
9-1-5) to promote less variation in peak and trough serum levels
With prolonged therapy, monitor renal, hepatic, and hematologic function
periodically |

|
|
Dosage Forms |
|
Capsule, as trihydrate: 250 mg, 500 mg
Powder for oral suspension, as trihydrate: 125 mg/5 mL (5 mL, 80 mL, 100 mL,
150 mL, 200 mL); 250 mg/5 mL (5 mL, 80 mL, 100 mL, 150 mL, 200 mL)
Powder for oral suspension, drops, as trihydrate: 50 mg/mL (15 mL, 30 mL)
Suspension, oral: 200 mg/5 mL; 400 mg/5 mL
Tablet, chewable, as trihydrate: 125 mg, 200 mg, 250 mg, 400 mg
Tablet, film coated: 500 mg, 875 mg |

|
|
References |
|
Boguniewicz M and Leung DY,
"Hypersensitivity Reactions to Antibiotics Commonly Used in Children,"
Pediatr Infect Dis J, 1995, 14(3):221-31.
Canafax, DM, Yuan Z, Chonmaitree T, et al,
"Amoxicillin Middle Ear Fluid Penetration and Pharmacokinetics in Children with Acute Otitis Media,"
Pediatr Infect Dis J, 1998, 17(2):149-56.
Dajani AS, Taubert KA, Wilson WW, et al,
"Prevention of Bacterial Endocarditis. Recommendations by the American Heart Association,"
JAMA 1997, 277(22):1794-801.
Donowitz GR and Mandell GL, "Beta-Lactam Antibiotics," N Engl J Med,
1988, 318(7):419-26 and 318(8):490-500.
Dougall HT, et al,
"The Effect of Amoxicillin on Salivary Nitrite Concentrations: An Important Mechanism of Adverse Reactions?"
Br J Clin Pharmacol, 1995, 39(4):460-2.
Hautekeete ML, Brenard R, Horsmans Y, et al,
"Liver Injury Related to Amoxycillin-Clavulanic Acid: Interlobular Bile-Duct Lesions and Extrahepatic Manifestations,"
J Hepatol, 1995, 22(1):71-7.
Hill S, Yeates M, Pathy J, et al,
"A Controlled Trial of Norfloxacin and Amoxicillin in the Treatment of Uncomplicated Urinary Tract Infection in the Elderly,"
J Antimicrob Chemother, 1985, 15(4):505-6.
Jones KH and Hill SA,
"The Toxicology, Absorption and Pharmacokinetics of Amoxicillin," Adv Clin
Pharmacol, 1974, 7:20.
Oe PL, et al,
"Pharmacokinetics of the New Penicillins, Amoxicillin and Flucloxacillin in Patients With Terminal Renal Failure Undergoing Hemodialysis,"
Chemotherapy, 1973, 19:279.
Parry MF, "The Penicillins," Med Clin North Am, 1987, 71(6):1093-112.
Prignet JM, Galzin M, Duval JL, et al,
"Amoxicillin-Induced Esophageal Ulcer With Intractable Hiccups as the Presenting Manifestation,"
Semaine des Hopitaux, 1995, 71:186-7.
Westphal JF, Jehl F, Brogard JM, et al,"Amoxicillin Intestinal Absorption
Reduction by Amiloride: Possible Role of the Na+-H+
Exchanger," Clin Pharmacol Ther, 1995, 57(3):257-64.
Wright AJ, "The Penicillins," Mayo Clin Proc, 1999, 74(3):290-307.
Wynn RL, "Amoxicillin Update," Gen Dent, 1991, 39(5):322,4,6.
|

|
Copyright © 1978-2000 Lexi-Comp Inc. All Rights Reserved
| |